In order to simplify the structure of paths to several library/objects in the recent Pd-extended releases, a <pd-externals> folder is created during the installation.

I would generally recommend to make use of that folder for one's own library/objects and other libs.

I don't entirely follow what is happening with your files. But in order to
access abstractions they need to have a file path, which you can setup via
the preferences menu>>>Path. I don't know if you are aware of this or not.

I put all mine in a folder called "abstractions" which I have set up a path
to.